Elf Strikes Back

For Elf McEager:
You have been assigned an ID number for your audit of the system: ODIzODI5MTNiYmYw . Use this to gain access to the upload section of the site.
Good luck!

Task

• What string of text needs adding to the URL to get access to the upload page?

  /?id=ODIzODI5MTNiYmYw
  

• What type of file is accepted by the site?

  image           -via page source code
  

• In which directory are the uploaded files stored?

  /uploads/
  

• Activate your reverse shell and catch it in a netcat listener!

  no answer      -via upload php-reverse-shell with .jpeg.php extention
  

• What is the flag in /var/www/flag.txt?

  [redacted challenge flag]